(1) Field of the Invention
The present invention relates to a narrow band compensating beamformer for a receiving array and more particularly to a compensating beamformer for an array that conforms to some surface other than a plane, thus being three dimensional, where the output signal of each array sensing element is delayed or phase shifted in such a fashion as to produce the equivalent array one would get by projecting each hydrophone onto a plane at some desired orientation. Low side lobe shading techniques available for planar arrays can then be used to improve performance.
(2) Description of the Prior Art
Conformal arrays do not generally lend themselves to efficient low side lobe shading and for this reason the side lobe behavior of conformal arrays is inferior to that of planar arrays.
The Navy has long used planar array sensors for torpedoes and other craft. There are instances however when it is more advantageous structurally to have array sensing elements conform to a non-planar surface of the vessel which carries it. Unfortunately, experience has shown that these conformal arrays exhibit higher side lobe behavior which does not readily lend itself to low side lobe shading techniques. When is needed is an array beamformer which allows effective shading of the side lobes which result from the signals received from a conformal array.